FOR A LONG TIME OP ART has occupied a position similar to that of the bouffant hairdo. Briefly fashion-forward, it quickly became an embarrassment. Almost as soon as Op debuted, it degenerated into one of the most visibly dated features of the ’60s. Fleeting reappearances in subsequent decades took place through appropriations—both cynical and affectionate—by younger figures for whom its retro quality was the salient feature. So, with a few exceptions, paintings associated with the Op moment have languished in museum storerooms, and the various jigsaw puzzles, pot holders, and lunch boxes that had been adorned with moiré patterns wore out their welcome in family rooms around the country and sold for pennies at garage sales. Now, with the New York Times announcing the return of Op to industrial design, and with several exhibiting institutions currently showcasing objects by the likes of